An Orthogonal Frequency Division Multiplexing (OFDM) scheme transmits data by using a multi-carrier. The OFDM scheme is a form of Multi-Carrier Modulation (MCM) scheme that converts a serial input symbol sequence into parallel symbol sequences and transmits the same through respective orthogonal subcarriers.
FIG. 1 is a diagram illustrating a pilot structure according to the related art.
Referring to FIG. 1, in the OFDM scheme, a transmitter may dispose pilot symbols in a two-dimensional structure of a time (symbol) axis and a frequency (subcarrier) axis. Accordingly, as compared with other systems, a receiver is advantageous in estimating a channel having multipath fading characteristics.
The receiver demodulates and decodes a data symbol by using channel information estimated by using a pilot symbol included in a signal received from the transmitter. Accordingly, a channel estimation performance improves as the number of pilot symbols increases. However, in the wireless communication system, since the number of data symbols decreases as the number of pilot symbols increases, the number of pilot symbols allocatable to signals is limited.
When the channel estimation performance degrades due to a limited number of pilot symbols, the performance of the wireless communication system may degrade. Therefore, the wireless communication system requires a scheme for reducing a channel estimation error.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.